Custom cables: double wire alternative

[LePhuronn]

Greetings. I'm starting on a custom set of PSU cables very soon and not looking forward to the double-wire tomfoolery that's coming with Corsair's lovely 10+18 to 24 arrangement. Let me ask this then...

...can we replace this:

With this?

The latter will be a lot easier to make and cleaner to sleeve and route, and I'm sure I've seen it done before somewhere. It's certainly done on 6+2 GPU cables to get the extra ground wires in, but on my PSU (SF600 Platinum) the double wires are for 3.3V, 5V and a ground.

Is this doable, or am I going to have to get the soldering iron out for some annoying T-splice action?

Cheers.

 

[DaleTheWhale]

Appreciate this is a few weeks old, but me and the girlfriend are looking at alternatives to this as well, although soldering a splicing doesn't seem too much of a hassle (we have 4 double wires to do!).

Is this doable, or am I going to have to get the soldering iron out for some annoying T-splice action?

Cheers.

Did you go ahead with soldering or find a better solution?

 

[LePhuronn]

Did you go ahead with soldering or find a better solution?

Unsurprisingly for this project, I've not really done anything yet beyond reading up on my specific PSU and the purpose of sense wires. We discuss this on pages 15 and 16 of my Asteria II build log, but in a nutshell for my PSU specifically (SF600 Platinum) the sense wires must be present for the unit to even turn on. However, because I'm only doing 20-30cm max runs, I can reduce the gauge of the sense wire to some thin-wall 24AWG, and combined with the thin wall 17AWG I'm already using I can run both wires inside the same piece of sleeving. No soldering or splicing required, just crimp both wires into the same connector and then have them split off well away out of sight at the other end.

It'll work in concept

The trouble is though even with 2 wires inside, that 550 paracord is still a bit baggy at full stretch, plus has a noticeably different weave pattern to the 325 paracord I'm using everywhere else. This is purely an aesthetic obstacle to this idea, the principle is sound. Failing that I will just t-splice the wires as my napkin maths show the voltage drop over 30cm runs of 17AWG wire will be negligible, so the sense wires are arguably redundant.

So essentially if your choice of sleeving can fit 2 wires inside then you could try this out. Otherwise it depends on how comfortable you feel changing the operation of the PSU. Double wires usually incorporate a sense wire, and the sense wire needs to be as close to the component as possible to measure voltage drops; the further away it is, the less accurate it becomes. But then 18AWG wire loses about 0.15V per metre, so how significant is this for your system in practical terms?

 

[DaleTheWhale]

But then 18AWG wire loses about 0.15V per metre, so how significant is this for your system in practical terms?

You've certainly done your research, not heard anything about sense wires in my past few days reading so that's interesting to know. The longest cable we'll be running is about 40cm so looks like that won't be much of an issue? We're using 18AWG but the sleeve wouldn't fit another cable through as well unfortunately, so might not be able to do as you've done in your image and go with the split wire approach as we have access to a soldering iron.

A related question as you'll likely know the answer, we have the pinout design for one power supply we're doing, but the design we have for another is OK, but flaky. In reality if we still have the original cables, it's a simple as following each wire from the mobo end to PSU end to get the diagram? That should give us everything we need minus what voltage/type that wire is?

 

[LePhuronn]

Yeah, just follow the existing cables and draw your own diagram. I had to do that with my SF600 because I found 2 different pinouts on t'interweb. Always worth checking.

As for wire types and voltages, the chunkier power units are starting to use 16 AWG now, but the sense wire that makes up a double wire is specced at 22 AWG. When you're tracing the routes back have a feel to see if one wire is thinner than the other, that'll be your sense wire. If you map the wires routes you won't need to worry about what the voltages are, but you can always look up the ATX spec for a 24 pin to see what the motherboard expects and then map voltages on your diagram.